fix: fix depends builds on FreeBSD hosts

[kwvg]

Additional Information

Despite builders for BSD-based platforms being backported as early as dash#5362, they didn't work on account of using a curl flag, --retry, that was lopped off other builders in dash#3003 as a way to mitigate aberrant Travis CI-specific behaviour.

As the variable $(DOWNLOAD_RETRIES) was removed as part of that mitigation, the introduction of builders that rely on this variable caused failures as the flag was accompanied by nothing. As our CI host isn't based on FreeBSD, this went unnoticed. When deciding between extending the existing patch and reverting it, reverting it proved to be more attractive on account of us no longer using Travis CI and the revert bringing us closer to upstream.

Additionally, the std::unary_function patch that was introduced in dash#5610 proves to be necessary on BSD-based platforms as well (had to be extended for and tested on GhostBSD, based on FreeBSD 13.2-STABLE, Clang 16). Instead of conditionally patching based on platform and compiler, a more reliable patch would be to downgrade the C++ version used to build Boost at the last version to have std::unary_function, which would be C++11, albeit deprecated (source).

Though it's likely this route wasn't taken originally due to compiler errors that happened despite downgrading to C++11. These errors were due to the compiler objecting to std::unary_function usage in Boost headers, despite the backport of bitcoin#25436, which should've solved this problem. The reason the errors were still persisting is because the necessary flag, -DBOOST_NO_CXX98_FUNCTION_BASE, was only applied if --enable-suppress-external-warnings was set. CI didn't catch this, as the flag is always set, to keep log lengths manageable. This has been rectified.

All changes combined, one should be able to build non-Qt Dash binaries using depends though building the Qt client from depends unfortunately remains a problem, even upstream (source, source).

Demo

Based on bbc9957

Built using:

• depends flags: NO_QT=1 ALLOW_HOST_PACKAGES=1 HOST=x86_64-unknown-freebsd13.2
• configure flags : --prefix=$(pwd)/depends/x86_64-unknown-freebsd13.2 --enable-debug --enable-suppress-external-warnings --with-gui
• Qt installed using pkg (qt5)

Checklist:

• I have performed a self-review of my own code (note: N/A)
• I have commented my code, particularly in hard-to-understand areas (note: N/A)
• I have added or updated relevant unit/integration/functional/e2e tests (note: N/A)
• I have made corresponding changes to the documentation (note: N/A)
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[UdjinM6]

Compiled with no issues on macos 14.5, Apple clang version 15.0.0 (clang-1500.3.9.4)

light ACK bbc9957

[knst]

could you add TODO here so far as it is not permanent change?

[kwvg]

Mentioned it in https://github.com/dashpay/dash-issues/issues/53

[knst]

I meant TODO right here, so, next release we can re-evaluate it if it is still necessary or can be removed, but I guess you should not forget it yourself :D

[PastaPastaPasta]

utACK bbc9957

[knst]

ACK bbc9957

got a build succeed with gcc-13.2.0-4ubuntu3 on ubuntu (not freebds though)